EP 1291447 A4 20040519 - COLD-ROLLED STEEL SHEET HAVING EXCELLENT STRAIN AGING HARDENING PROPERTIES AND METHOD FOR PRODUCING THE SAME
Title (en)
COLD-ROLLED STEEL SHEET HAVING EXCELLENT STRAIN AGING HARDENING PROPERTIES AND METHOD FOR PRODUCING THE SAME
Title (de)
KALTGEWALZTES STAHLBLECH MIT AUSGEZEICHNETEN RECKALTERUNGSEIGENSCHAFTENUND HERSTELLUNGSVERFAHREN FÜR EIN SOLCHES STAHLBLECH
Title (fr)
TOLE D'ACIER LAMINEE A FROID PRESENTANT D'EXCELLENTES PROPRIETES DE RHEODURCISSEMENT PAR VIEILLISSEMENT, ET PROCEDE DE PRODUCTION
Publication
Application
Priority
- JP 0101002 W 20010214
- JP 2000162498 A 20000531
Abstract (en)
[origin: EP1291447A1] The present invention provides a cold-rolled sheet exhibiting superior strain-aging hardenability which is suitable for use in automobile bodies, and a method for manufacturing the same. In particular, a slab including, by mass, not more than 0.15% carbon, not more than 0.02% Al, and 0.0050% to 0.0250% nitrogen in which Si + Mn/5 + 10P is adjusted to less than 0.44 and the ratio N/Al is adjusted to not less than 0.3 is hot-rolled at a finish-rolling delivery temperature FDT of not less than 800 DEG C, and then coiled at a temperature of not more than 650 DEG C. Next, after cold-rolling, continuous-annealing at a temperature between the recrystallization temperature and 950 DEG C, primary cooling for cooling to a temperature zone of not more than 500 DEG C, and overaging in the temperature zone of 350 DEG C to 450 DEG C for a retention time of not more than 30 seconds are performed to prepare a steel sheet containing not less than 0.0010% of solute nitrogen and having a structure in which the ferrite phase with the grain size of not more than 15 mu m is included at a ratio of not less than 90%, the remainder of the structure being the pearlite phase. The resulting steel sheet has superior strain-aging hardenability in which the tensile strength is less than 440 MPa and the yield ratio is less than 70%.
IPC 1-7
IPC 8 full level
C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C21D 9/52 (2006.01)
CPC (source: EP KR US)
C21D 8/0273 (2013.01 - EP US); C22C 38/001 (2013.01 - EP US); C22C 38/04 (2013.01 - EP KR US); C22C 38/06 (2013.01 - EP US); C21D 8/0226 (2013.01 - EP US); C21D 8/0236 (2013.01 - EP US); C21D 8/0242 (2013.01 - EP US); C21D 9/52 (2013.01 - EP US); C21D 2211/005 (2013.01 - EP US); C21D 2211/009 (2013.01 - EP US); Y02P 10/20 (2015.11 - EP US)
Citation (search report)
- [A] EP 0943696 A1 19990922 - KAWASAKI STEEL CO [JP], et al
- [A] PATENT ABSTRACTS OF JAPAN vol. 011, no. 136 (C - 419) 30 April 1987 (1987-04-30)
- [A] PATENT ABSTRACTS OF JAPAN vol. 016, no. 283 (C - 0955) 24 June 1992 (1992-06-24)
- [A] PATENT ABSTRACTS OF JAPAN vol. 2000, no. 08 6 October 2000 (2000-10-06)
- See references of WO 0192593A1
Designated contracting state (EPC)
BE DE FR GB IT
DOCDB simple family (publication)
EP 1291447 A1 20030312; EP 1291447 A4 20040519; EP 1291447 B1 20050504; CA 2380377 A1 20011206; CA 2380377 C 20070109; CN 1152970 C 20040609; CN 1386141 A 20021218; DE 60110586 D1 20050609; DE 60110586 T2 20051201; KR 100611541 B1 20060810; KR 20020036838 A 20020516; TW 500809 B 20020901; US 2003047257 A1 20030313; US 6695932 B2 20040224; WO 0192593 A1 20011206
DOCDB simple family (application)
EP 01906127 A 20010214; CA 2380377 A 20010214; CN 01802260 A 20010214; DE 60110586 T 20010214; JP 0101002 W 20010214; KR 20027001333 A 20020130; TW 90103207 A 20010214; US 3174202 A 20020123